Cast Doomsday by paying ({B} magic symbol) ({B} magic symbol) ({B} magic symbol) , searching your library and graveyard for Torch Courier, Kiki-Jiki, Goblin Firestarter, Brazen Buccaneers and Conspicuous Snoop, exiling all other cards from your graveyard and library, and then placing the remaining cards on top of your library in the order previously listed and losing half your life, rounded up.
Activate Grenzo by paying ({2} magic symbol) , putting Conspicuous Snoop into your graveyard and then onto the battlefield.
Cast Torch Courier from the top of your library by paying ({R} magic symbol) .
Activate Torch Courier by sacrificing it, giving Conspicuous Snoop haste until end of turn.
Activate Conspicuous Snoop using Kiki-Jiki's ability by tapping it, creating a token copy of Conspicuous Snoop with haste.
Repeat step 5 with the new Conspicuous Snoop token an arbitrarily large amount of times.
Activate Grenzo by paying ({2} magic symbol) , putting Brazen Buccaneers into your graveyard and then onto the battlefield.
Brazen Buccaneers enters the battlefield, revealing Kiki-Jiki, putting a +1/+1 counter on Brazen Buccaneers and putting Kiki-Jiki into your graveyard.
Activate a Conspicuous Snoop using Goblin Firestarter's ability by sacrificing it, dealing 1 damage to any target.